The present disclosure relates to an electrode material, an electrode, and a battery.
Electrodes having an ability to catalyze oxygen reduction (hereafter, may be referred to as “oxygen reduction electrode”) are used in various types of batteries, electrodes, and sensors such as:
(A) enzymatic biofuel cells that use organic matter such as sugar, alcohol, or cellulose as a fuel;
(B) microbial fuel cells used in wastewater treatment or sludge treatment, in which a reaction is caused using organic matter contained in the wastewater or sludge to decompose the organic matter;
(C) metal-air batteries that include a negative electrode with a negative-electrode-active material including a metal and an alloyed material;
(D) various types of fuel cells such as a polymer electrolyte fuel cell, a phosphoric-acid fuel cell, a molten carbonate fuel cell, a solid-oxide fuel cell, an alkaline fuel cell, and a direct-methanol fuel cell;
(E) gas diffusion electrodes for oxygen reduction used in brine electrolysis; and
(F) electrochemical sensors for detecting oxygen.
An existing oxygen reduction catalyst, which constitutes the oxygen reduction electrode, having a remarkable ability to catalyze oxygen reduction is Platinum (Pt). However, because of the high price of platinum, there has been a strong demand for a replacement catalyst for platinum.
A metal-air battery including a negative electrode containing zinc, aluminium, or magnesium and a positive electrode containing at least one oxygen reduction catalyst is known from, for example, Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2012-517075. The metal-air battery disclosed in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2012-517075 includes an oxygen reduction catalyst containing a noble metal or the like, and the oxygen reduction catalyst is supported on carbon black, graphite, charcoal, activated carbon, or the like.